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Corollary Discharge Failure in an Oculomotor Task Is Related to Delusional Ideation in Healthy Individuals.

Malassis R, Del Cul A, Collins T - PLoS ONE (2015)

Bottom Line: Deficits in predictive activity, such as that afforded by a corollary discharge signal, have been reported in patients with schizophrenia, and may lead to the emergence of positive symptoms, in particular delusions of control and auditory hallucinations.Variation of the degree of self-generated movement knowledge as a function of the prevalence of delusional ideation in the normal population strongly supports the idea that corollary discharge deficits measured in schizophrenic patients in previous researches are not due to neuroleptic medication.We also propose that this difference in results between the perceptual and the motor tasks may point to a dissociation between corollary discharge for perception and corollary discharge for action.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes & CNRS, Paris, France.

ABSTRACT
Predicting the sensory consequences of saccadic eye movements likely plays a crucial role in planning sequences of saccades and in maintaining visual stability despite saccade-caused retinal displacements. Deficits in predictive activity, such as that afforded by a corollary discharge signal, have been reported in patients with schizophrenia, and may lead to the emergence of positive symptoms, in particular delusions of control and auditory hallucinations. We examined whether a measure of delusional thinking in the general, non-clinical population correlated with measures of predictive activity in two oculomotor tasks. The double-step task measured predictive activity in motor control, and the in-flight displacement task measured predictive activity in trans-saccadic visual perception. Forty-one healthy adults performed both tasks and completed a questionnaire to assess delusional thinking. The quantitative measure of predictive activity we obtained correlated with the tendency towards delusional ideation, but only for the motor task, and not the perceptual task: Individuals with higher levels of delusional thinking showed less self-movement information use in the motor task. Variation of the degree of self-generated movement knowledge as a function of the prevalence of delusional ideation in the normal population strongly supports the idea that corollary discharge deficits measured in schizophrenic patients in previous researches are not due to neuroleptic medication. We also propose that this difference in results between the perceptual and the motor tasks may point to a dissociation between corollary discharge for perception and corollary discharge for action.

No MeSH data available.


Related in: MedlinePlus

(A) Schematic illustration of first saccade endpoints (grey circles) and a few of the oblique second saccades needed to reach the second target. This schema omits second saccade variability to illustrate the idea of a correlation between first saccade error and second saccade horizontal component. (B) Individual correlation between first saccade error and second saccade horizontal component. (C) Distribution of the slope of the relationship between first saccade error and second saccade horizontal component for the population of subjects. The arrow corresponds to the mean value (0.87°).
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pone.0134483.g004: (A) Schematic illustration of first saccade endpoints (grey circles) and a few of the oblique second saccades needed to reach the second target. This schema omits second saccade variability to illustrate the idea of a correlation between first saccade error and second saccade horizontal component. (B) Individual correlation between first saccade error and second saccade horizontal component. (C) Distribution of the slope of the relationship between first saccade error and second saccade horizontal component for the population of subjects. The arrow corresponds to the mean value (0.87°).

Mentions: To measure the extent to which information about the first saccade was taken into account to plan the second saccade, we examined the relationship between the error on the first saccade and the obliqueness of the second saccade, in the memory-guided task. Indeed, if the first saccade undershot the first target location, then to acquire the second target location, the second saccade should be oblique, as illustrated in Fig 4A. Overshooting saccades should also lead to oblique second saccades but with a horizontal component in the opposite direction. The slope of the relationship between first saccade error and second saccade horizontal component is thus an index of the extent to which the metrics of the first saccade are corrected for in the second saccade. The strength (correlation coefficient) is an index of the precision of that correction. We fit the data with a linear relationship that allows for variance in both x and y.


Corollary Discharge Failure in an Oculomotor Task Is Related to Delusional Ideation in Healthy Individuals.

Malassis R, Del Cul A, Collins T - PLoS ONE (2015)

(A) Schematic illustration of first saccade endpoints (grey circles) and a few of the oblique second saccades needed to reach the second target. This schema omits second saccade variability to illustrate the idea of a correlation between first saccade error and second saccade horizontal component. (B) Individual correlation between first saccade error and second saccade horizontal component. (C) Distribution of the slope of the relationship between first saccade error and second saccade horizontal component for the population of subjects. The arrow corresponds to the mean value (0.87°).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549245&req=5

pone.0134483.g004: (A) Schematic illustration of first saccade endpoints (grey circles) and a few of the oblique second saccades needed to reach the second target. This schema omits second saccade variability to illustrate the idea of a correlation between first saccade error and second saccade horizontal component. (B) Individual correlation between first saccade error and second saccade horizontal component. (C) Distribution of the slope of the relationship between first saccade error and second saccade horizontal component for the population of subjects. The arrow corresponds to the mean value (0.87°).
Mentions: To measure the extent to which information about the first saccade was taken into account to plan the second saccade, we examined the relationship between the error on the first saccade and the obliqueness of the second saccade, in the memory-guided task. Indeed, if the first saccade undershot the first target location, then to acquire the second target location, the second saccade should be oblique, as illustrated in Fig 4A. Overshooting saccades should also lead to oblique second saccades but with a horizontal component in the opposite direction. The slope of the relationship between first saccade error and second saccade horizontal component is thus an index of the extent to which the metrics of the first saccade are corrected for in the second saccade. The strength (correlation coefficient) is an index of the precision of that correction. We fit the data with a linear relationship that allows for variance in both x and y.

Bottom Line: Deficits in predictive activity, such as that afforded by a corollary discharge signal, have been reported in patients with schizophrenia, and may lead to the emergence of positive symptoms, in particular delusions of control and auditory hallucinations.Variation of the degree of self-generated movement knowledge as a function of the prevalence of delusional ideation in the normal population strongly supports the idea that corollary discharge deficits measured in schizophrenic patients in previous researches are not due to neuroleptic medication.We also propose that this difference in results between the perceptual and the motor tasks may point to a dissociation between corollary discharge for perception and corollary discharge for action.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes & CNRS, Paris, France.

ABSTRACT
Predicting the sensory consequences of saccadic eye movements likely plays a crucial role in planning sequences of saccades and in maintaining visual stability despite saccade-caused retinal displacements. Deficits in predictive activity, such as that afforded by a corollary discharge signal, have been reported in patients with schizophrenia, and may lead to the emergence of positive symptoms, in particular delusions of control and auditory hallucinations. We examined whether a measure of delusional thinking in the general, non-clinical population correlated with measures of predictive activity in two oculomotor tasks. The double-step task measured predictive activity in motor control, and the in-flight displacement task measured predictive activity in trans-saccadic visual perception. Forty-one healthy adults performed both tasks and completed a questionnaire to assess delusional thinking. The quantitative measure of predictive activity we obtained correlated with the tendency towards delusional ideation, but only for the motor task, and not the perceptual task: Individuals with higher levels of delusional thinking showed less self-movement information use in the motor task. Variation of the degree of self-generated movement knowledge as a function of the prevalence of delusional ideation in the normal population strongly supports the idea that corollary discharge deficits measured in schizophrenic patients in previous researches are not due to neuroleptic medication. We also propose that this difference in results between the perceptual and the motor tasks may point to a dissociation between corollary discharge for perception and corollary discharge for action.

No MeSH data available.


Related in: MedlinePlus